title: Baseline dependency of minimal clinically important improvement.
abstract: BACKGROUND
  Minimal clinically important improvement (MCII) is the smallest outcome measure change important to patients. Research suggests that MCII is dependent on patients' baseline functional status measures.
  
  
  OBJECTIVE
  The purposes of this study were: (1) to confirm whether MCII is dependent on patients' admission scores and (2) to test whether MCII is dependent on selected demographic characteristics.
  
  
  METHODS
  This was a prospective, longitudinal, observational cohort study of 6,651 patients with orthopedic knee impairments treated in 332 outpatient rehabilitation clinics in 27 states in the United States.
  
  
  METHODS
  Patient self-reports of functional status (FS) from the Lower Extremity Functional Scale were assessed using a computerized adaptive testing application (0-100 scale).
  
  
  METHODS
  An anchored-based longitudinal method, with a 15-point Likert-type scale (-7 to +7), was used to provide a global rating of change (GROC). The MCII threshold for the GROC was defined at a cut-score of +3 or greater and was determined using nonparametric receiver operating characteristic curve analysis for each of the following variables: sex, symptom acuity, age group, and quartile of baseline FS scores.
  
  
  RESULTS
  The results showed that MCII was dependent on patient baseline and demographic characteristics. Patients who were male, were younger, had more-acute symptoms, or had lower FS scores at admission required more FS change to report meaningful change.
  
  
  CONCLUSIONS
  As this study was a secondary analysis, how the length of treatment mediated the relationship between the independent and dependent variables was unclear.
  
  
  CONCLUSIONS
  Although a single MCII index may provide a standard cut-score defining the smallest FS change that is meaningful to patients, researchers and clinicians should be aware that MCII is context specific and not a fixed attribute. Current results may help researchers, clinicians, and policy makers to interpret FS change related to the importance of the change to the patient.
authors.affiliation: Department of Occupational Science and Technology, University of Wisconsin-Milwaukee, PO Box 413, Enderis Hall 971, Milwaukee, WI 53201, USA. wang52@uwm.edu
authors.forename: Ying-Chih
authors.initials: YC
authors.lastname: Wang
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Hart
authors.forename: Paul W
authors.initials: PW
authors.lastname: Stratford
authors.forename: Jerome E
authors.initials: JE
authors.lastname: Mioduski
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D007718:Knee Injuries / Q000503:physiopathology* / Q000534:rehabilitation*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D026741:Physical Therapy Modalities; D011446:Prospective Studies; D012372:ROC Curve; D020127:Recovery of Function; D012737:Sex Factors; D014481:United States